hey guys.. So here is a brief summation of what's going to be happening and why. We all know the rotary engine is light and the chassis balance is superb. However I'm not 100% satisfied with all the work Mazda did all those years ago. Over the next while I'll be going through my 91 TII and will lighten, reinforce and ultimately drysump the engine. Why? Well as she sits the car is ready for about 500 to the wheels. 1600 cc injectors all around. Stage 3 extended port work. upgraded seals all around ect ect. But like I said that's not good enough. So my plan is to remove as much weight from the car as possible without sacrificing heat and air. I'm old so I need that stuff these days. And then dry sump the engine to lower it down in the chassis another 3 inches or so. The goal. Better handling and speed at a lower rwhp.

 

Doesn't "dropping" the engine 3" require dropping the clutch/transmission 3" as well?
How does that work?

I thought dry-sumping was all about combating starvation, not packaging/handling.

 

you can move around the center of gravity somewhat. lowering the engine would just be to put it much closer to the subframe Although I suppose you could make the argument that lowering the suspension does roughly the same thing. Anyway, I want the bottom of the engine sitting as low as possible. Part of the reason for this is because I plan on fabbing up a full under tray to try and pull the car down at speed as well. And by full I mean that I still plan to have provisions for the transmission cooling fins and diff. Just want to button things up down there as much as possible.

 

It seems like dry-sump with the engine as originally mounted would make the bellypan even easier to design.

 

He wants drop sump and to lower the motor down 3". I'd say go for it. I want to lower my motor.but move it 2" back. that's hopefully going to be he plan for.me with my next chassis.

 

I considered dry sumping my engine two years ago. Partly because I wanted to upgrade the NA oil pump (ultimately I just put in a TII pump) and partly because I wanted the "WOW!" factor.

However I didn't do it for a few reasons. First, the Mazda OEM dry sump front cover is insanely expensive. Mazdatrix quotes it as $3666.

So I gave up on that because there's no way I'd pay $4000 for the thing.

Next I investigated using a typical aftermarket dry sump pump. These are a LOT cheaper and are typically driven by a belt from the eccentric shaft. Would have been a simple task to fab up a bracket, machine a pulley, then make a dry sump oil pan with pickups (and a nice 1/4" stiffening panel). Then just a reservoir, some plumbing, and Bob's your uncle.

I didn't go this route because I was not happy with the idea of an oil pump driven by an external belt. For street use, it just reeked of a possible failure point that would leave me at the side of the road 400KM from my house with no oil pressure. Now I don't know if your car is a track only car, so this may not matter to you.

I then looked at modifying a front cover using a standard aftermarket dry sump pump and in internal chain drive. That would have been a LOT of work, so I gave up on that one pretty quickly.

If your car is track only, then fabbing up your own system is the way to go. I had my costs at just under $1500 which is totally reasonable. If it's street driven, then for reliability I'd say to bite the bullet and go with the OEM system.

 

^ i was thinking about what Aaron was talking about, do u know how much this is? ive thought (dreamed) about it but then quickly forget about it every time i look up the price. That being said, i think it would be an awesome thing to do, for handling, reliability, and over all awesomeness, i say go for it if you have the money....

 

I picked up a 4 stage oil pump for 400 on eBay last week. So, most of the expense is already covered, and i have some ideas about how to modify the front cover and run the pickups.

 

I think he's mostly correct on this, the topic is Pinion Angle.
http://www.ssz28.com/tech/Pinionangle.html
http://www.hotrodhotline.com/md/html..._harmonics.php

Just for starters, read the stuff above.


Also, share with us the plan for the replacement oil system.
where did you plan on tapping the irons, etc for the new supply of oil?

 

My plan for the pickups was a simple 1/4" plate on the bottom of the engine, with two small sumps, one at the front, one at the back.

I was going to locate my reservoir in the former charcoal canister location by custom making a tank to fit that shape. Then just feed oil into the stock rear iron feed, with a plug in place of the oil pressure regulator.

Oh, and don't forget a Hobb switch so if you lose oil pressure, power to the EMS is cut!

I look forward to seeing the build.

 

You and i are thinking on a very similar path.

 

How do you know the pump can supply the 13B with enough flow and pressure?

I'd use 1/2" 6061 and run the pickups through the plate. One pickup split to the front and one split to the rear so each corner has a suction hole.

The tank should be mounted as low as possible.

How do you plan to lower the transmission? I've never seriously though about it but would spacers work? Like a reverse body lift on a jeep?

 

http://www.pineappleracing.com/custo...ldingsvcs.aspx

Pineappleracing offer dry sump modifications for $3k
if you're not interested in that (and it seems you aren't and are going custom) I am sure they would be able to answer your questions.

 

Almost all of the used pumps on the market are made for V8s and many are ex NASCAR stuff. No issue really. Pressure is either externally adjustable via a regulator or adjustable via an internal regulator/bypass on the pump.

The tank can be mounted anywhere. Nice and high is quite useful for degassing. Low for weight distribution of course but mounting locations are limited.

Man, all this discussion is making me think about it again.

 

It seems like a lot of effort for very little gain.
What do you think the car will weigh once you've done everything except lowering the engine?
Then, how much do you think lowering the engine 3" will affect the cars overall CG?
Then how much benefit to the handling will that change in CG add. And most importantly will it be noticeable for the cars intended use?
These changes might be worth a couple tenths on a track. But if it's just a fun street car, then I contend that all this work would not change the car that much.
Don't mean to crap on your idea, but there is a reason this type of work is really only done on race cars.

 

Can you expand this a little more and explain what you mean by degassing?

Do you mean removing the air bubbles from the oil? The tanks I've seen noramlly have a swirl pot design with a fine screen mesh to allow the oil and air to separate. The oil enters at an angle to the inner wall so it swirls around before passing through the mesh then settling into the bottom. I don't see how the tank's height in relation to the pump will help. Did I misinterpret what you meant by degassing?

 

Basically removing air/gas bubbles as you suggest. Having the tank a bit high also helps any bubbles trapped in the froth of the fluid as well as anything in the suction lines. Not a huge deal, I'll give you that. But honestly, it really doesn't matter where the tank goes.

 

In Slevin's case it matters a lot, I should think.
As his stated goal is to dry sump not for performance reasons but to lower the car's CG, the tank/lines/all associated parts would need to be as low as possible so as to not negate the gains from lowering the engine/tranny (which I don't think is really possible anyway).

 

Lowering the car's CG isn't done for performance? Even cars that never turn need low CG's

 

I failed at recognizing the bleeding obvious.